Selectable torque transfer mechanism for a vehicle transmission

Abstract

A vehicle powertrain includes an internal combustion engine having a crankshaft coupled to a flywheel having a ring gear. The powertrain also includes a transmission having an input shaft coupled to the flywheel and a brake mechanism having a pivotable rocker configured to selectively inhibit crankshaft rotation. The brake mechanism also includes an electric actuator configured to drive a plunger in connection with a first end of the rocker, wherein the first end engages the ring gear in a first position to inhibit forward rotation and a second end of the rocker engages the ring gear in a second position to inhibit rearward rotation.

What is claimed is: 
     
       1. A vehicle powertrain comprising:
 an internal combustion engine having a crankshaft coupled to a flywheel having a ring gear; 
 a transmission having an input shaft coupled to the flywheel; and 
 a brake mechanism having a pivotable rocker configured to selectively inhibit crankshaft rotation, and an electric actuator configured to drive a plunger in connection with a first end of the rocker, wherein the first end engages the ring gear in a first position to inhibit forward rotation and a second end of the rocker engages the ring gear in a second position to inhibit rearward rotation, and wherein the plunger extends toward a center of the ring gear to cause the first end to engage the ring gear and retracts away from the center of the ring gear to cause the second end to engage the ring gear. 
 
     
     
       2. The vehicle powertrain of  claim 1  wherein the rocker defines a third position that allows both uninhibited forward rotation and rearward rotation of the ring gear. 
     
     
       3. The vehicle powertrain of  claim 2  wherein neither the first end nor the second end of the rocker engages the ring gear when the rocker is in the third position. 
     
     
       4. The vehicle powertrain of  claim 2  wherein the electric actuator is a solenoid having a biasing member configured to urge the plunger to a neutral position when the solenoid is not energized. 
     
     
       5. The vehicle powertrain of  claim 1  wherein the electric actuator is a solenoid and a first polarity current supplied to the solenoid extends the plunger to define the first position of the rocker, a negative current retracts the plunger to define the second position of the rocker, and an absence of current supplied to the solenoid drives the plunger to a neutral state to define a third position of the rocker. 
     
     
       6. The vehicle powertrain of  claim 1  wherein the electric actuator is a solenoid and the solenoid includes a first coil to extend the plunger when energized to define the first position of the rocker, a second coil to retract the plunger to define the second position of the rocker, and a biasing member to urge the plunger to a neutral position when neither the first coil nor the second coil is energized. 
     
     
       7. A vehicle powertrain comprising:
 an internal combustion engine having a crankshaft coupled to a flywheel having a ring gear; 
 a planetary gear set having a sun driveably connected to a first electric machine, a carrier coupled to the flywheel, and a ring driveably connected to a differential; 
 a second electric machine driveably connected to the differential; and 
 a brake mechanism having a solenoid configured to drive a first end of a rocker to selectively inhibit crankshaft rotation, wherein the solenoid drives the first end toward a center of the ring gear to inhibit forward rotation and drives the first end away from the center to inhibit rearward rotation, and wherein the rocker selectively engages at least one of a plurality of gear teeth of the ring gear to inhibit rotation. 
 
     
     
       8. The vehicle powertrain of  claim 7  wherein the solenoid defines a neutral position where neither forward rotation nor rearward rotation of the crankshaft is inhibited by the rocker. 
     
     
       9. The vehicle powertrain of  claim 8  wherein the solenoid includes a biasing member configured to urge the solenoid to the neutral position when the solenoid is not energized. 
     
     
       10. The vehicle powertrain of  claim 7  wherein a second end of the rocker engages the ring gear when the first end is driven away from the center of the ring gear. 
     
     
       11. The vehicle powertrain of  claim 10  wherein the solenoid includes a plunger connected to the first end, and a first polarity current supplied to the solenoid extends the plunger to cause the first end to engage the ring gear, a negative current retracts the plunger to cause the second end to engage the ring gear, and an absence of current supplied to the solenoid drives the plunger to a neutral state to cause a third position of the rocker. 
     
     
       12. The vehicle powertrain of  claim 10  wherein the solenoid includes a plunger connected to the first end and a first coil to extend the plunger when energized to define a first position of the rocker, a second coil to retract the plunger when energized to define a second position of the rocker, and a biasing member to urge the plunger to a neutral position when neither the first coil nor the second coil is energized. 
     
     
       13. A transmission comprising:
 a flywheel having a ring gear adapted for fixation to a crankshaft of an internal combustion engine; 
 an input shaft coupled to the flywheel; and 
 a brake mechanism having a pivotable rocker configured to selectively inhibit crankshaft rotation, and a solenoid configured to drive a first end of the rocker to a first position to engage the ring gear to inhibit forward rotation, and to drive the first end to a second position to cause a second end of the rocker to engage the ring gear to inhibit rearward rotation, wherein the solenoid includes a plunger pivotally connected to the first end of the rocker, and wherein the solenoid drives the plunger toward a center of the ring gear to inhibit forward rotation and drives the plunger away from the center to inhibit rearward rotation. 
 
     
     
       14. The transmission of  claim 13  wherein a first polarity current applied to the solenoid extends the plunger to define the first position, a negative current retracts the plunger to define the second position, and an absence of current applied to the solenoid drives the plunger to a neutral state to cause a third position of the rocker. 
     
     
       15. The transmission of  claim 13  wherein the solenoid defines a neutral position where neither forward rotation nor rearward rotation of the crankshaft is inhibited by the rocker. 
     
     
       16. The transmission of  claim 15  wherein the solenoid includes a biasing member configured to urge the solenoid to the neutral position when the solenoid is not energized.